Propeller control



March 28, 1950 H. M. G EYER ETAL PROPELLER CONTROL Filed Nov. 20, 1946 2Sheets-Sheet 1 mmw 3 wk $5 TV D .7 N25. N fi M Mm m mm mm HH .BY J

H. M. GEYER ET AL March 28, 1950 PROPELLER CONTROL Filed uovizo, 194sNVENTORS Hnwdrd MEByer v/Inward Ea r5011 4/ ,MW-J

ATTORNEYS Patented Mar. 28, 1 950 UNL'IIE!) F'STATES PATENT OFFICE""PROPELLER CONTROL I Howard- M. .GeyerQ-Dayton, Ohio, :and; HowardCarson, Cambridge, Mass, assignors-to General Motors Corporation,Detroit, Mich., a.'corpora- ,tion of. Delaware FApplication November 20,1946, Serial-No'. .711,028

7.,Claims. =1 :ifI-his-inuentionu'elatesqto controls :for aircraft.spropelleraqand .has for. aanpbject overriding the :automaticwontrolwith-manualor other control .xmeansitogassist tcornect, lorwaugment theautoomaticz-control.

Another object of the inventionv is to-provide -aux-auxiliarys-control-ifor;- constant speed pro- .mellerszthat mayasuitrthe needs of.- .pilotsin inci- .-;dental:.and unusual maneuvers of line-aircraft.

.eAnother object .of:.ithe-.r,invention is to provide.

am-auxiliary: control-assembly that is adapted .;:to; becrinstalled; on.existinglapparatus notdesignedefor voverridez-control.

.nstilluanother object ofthe iinventioni-isto. pro- --ideeanvauxiliaryz-oontrol for .a self-contained-.constant;s1aeed-;propeller-forefiectinga-selectable -=measured=.-ineremental shift :of the propeller -mechanism-,; of: an instantaneousshift of greater --magnitude.. to fit: the existing conditions.

'i Yetanother object ofithe' invention is to pro-.

1 is-a schematic -drawing' in section of a propeller mechanism embodyingthe instant invention.

Fig: 2-is aperspective view of the control linkage Of :the 2 presentinvention 1 segregated from .thenpropellen mechanism.

The foregoing objects and advantages are ac- =cmplished lam-providing; asmall-electric motor e-With argreat:.-speedreduction.- gearing that is"adapted: to actuate the customary control lever -.'0f'- the:propellerhmechanism, with a source of electric. energy andswitches forselectively= actu- -.ating thernotor. The-motor-is one-0f thew-typezassociatedewith or..havinga built-in: brake .for suddenly arrestingrotation of the motor :in either direction promptly on interruption ofdriving energy. Thegearing is provided with a normally: engaged: but:separable clutch. so that the motor isv-normallyconditioned-to; actuatethe --controL l'ever of "the ;-:-propeller mechanism. iA- twopositioniswitch controls ithe:=direction=of .able to. reset; theautomatic constantspeed con- -trol-.and apply-histselected:control.Itwis: also necessary that .the automatic'control'zbe restored rotationand the amount of rotation of the-motor,

while a lever or manual linked'aforactuatingthe le ntrol lever ,ofsithe-propeller alsoincorporates a-- switch-adaptedito energize a-solenoidOil-1 17118 clutchuforlinterrupting .the gear connectionifrom the motorvwhenrzmovlernlent;of. the manual is to effect l actuation; of thepropeller 3 control zl-ever.

In aircraft: fitted-iwithatconstant;speed pro- --peller.=installationsmthere :frequentlyuarise; conditions when; it isidesirableior necessary to. :make

a furtheradjnstmentmf: the rblade..=pit'ch position :.to.fitrathe:..needsri0f;ifiight. r'l hei desired adjust-,menamawbeaismalkoritrmambeuof great magnitilde,- and the;constant-speedlcontrolmechanism usually is not: disposed ;.to' make.the;- adi ustment. It '.-may be ina-order; to shift: the; pitch: only a-:iew

degrees; while;ieelingethespointeof best. setting, or it may benecessarys.;to:shiftr. to; a feathered position, or. even.ascraftobrak-ing" position. In anyinstance" it is snecessary ethat the:-pilot -:be

at: any-instant; that, heseleots.

- Referring. :particularly :to the drawings; 1. and

: first with: respect-:tQ-Fig. 1;; an? engine :nosing? or supportingstructure .Jisnndicated at H) 'from which extends a: propellersshait l2' supported by ananti-friction .bearing-= M; the shaft 1 2 1 havingsplined drivingaconnec'tion at l6-rwith. axpropeller hub 'l 8 rand:retained-z thereon :in any suitable 'manner as by; the.usualshub-shaftnut-28. The

hub 18; provides sockets .1 22 -:within which. are -journalled for:rotati'on .blades 24 through: the

= agency of stack bearings: 26:,and. preloadbearing 28 supported by a;bladewbossu 30. 1 Withinmthe shank of the bladdfl 4- thereis a hydrauliccylinden 32:.maintainedein driving relation with the :blade by-pins ordowelsafldaextending through-a blade gear2 36,-: al flangefl ofthevcylinder and into. the-end: of. theilbladeoshank. A'I'PiSliOll'f'dfl.within the. cylinder-s32; has-helical splinedr connections between thecylinder 32;- arspindle :42 extending? :fromnbla'de':bOSSsfilichxaS;indicated ate. 44; .anda-4B,.so:-that ilinea-li movement of: the

piston-.4 0 within. the :cylinden '32 will-elicctrotation ofthetblade-flkabout its; axis on the:bearing 26 anch28.

, For actuating-the.- piston a'ifluidnpressuie: =line 48.;in. the:hubfl8-.zextendszalongthe spindle-:42

to the cut endrof the-icylinder, while a second carried rearwardlyiromethe-hub ill to conduits '52 .and flthat communicate withithedistributing ports of a governor vaive 56 situated in a hydraulicregulator 58 mounted on and rotatable with the propeller. The propellermay embrace any number of blades, and it is understood that all have thecylinder and piston with fluid connections .to the conduits 52 and 54 sothat all pistons will be actuated at the same instant and to the sameamount. A master gear 59 engaging all of the blade gears 36 correlatesthe action of all of the blades. The master gear isjournailed within theforward end of the hub I8 by suitable bearings, such as at 60 thatsurrounds a concentrically mounted accumulator 62 that is disposedaxially in front of the propeller shaft I2. The accumulator comprises arigid cylinder housing a skirted piston 64 that divides the cylinderinto a preload compartment 66 charged through a filler valve 68, and apressure compartment 70 chargeable and exhausting through a passage I2threading through the hub I8 to .an accumulator control valve assemblyI4 situated in the regulator 58.

The regulator is usually afflxed at the rear of the hub and mounted on arear extension thereof so as to rotate with the propeller, and providesa reservoir or annular chamber 16 normally closed to outside air. Thereservoir contains a quantity of oil or other pressure operating fluid.the medium by which the control of blade pitch is effected. Pressurecontrol valve mechanism and pressure developing mechanism are housedwithin the reservoir and may include the governor valve 56 from whichthe control lines 48 and 50 extend to the blade cylinders, and to whichextends a pressure supply line I8 fed by a pump 80. The governor valveassembly 56 embodies a plunger 82 that is in itself a centrifugallyresponsive member and is linked to a lever 84 oscillating over a movablefulcrum roller 86 against the yielding force of a rigidly supportedspring 88, the plunger 82 having a pair of spaced lands 90 and 92adapted when the plunger is in the equilibrium position to cover portsin the governor leading to the control lines 52 and 54. The fulcrumroller is mounted on a carriage 94 movable along guideways 96 by ashiftable control ring 98 as will presently appear, and due to which therelation of centrifugal force acting upon the valve plunger- 82 iswithin the control of the pilot. That givesthe pilot an exact control ofthe speed level at which the governor valve will control the propellerto constant speed. In other words movement of the fulcrum roller selectsthe constant speed at which the governor will maintain the propellermechanism. In so operating, the governor in responding to changes ofcentrifugal force, administers the fluid under pressure coming in fromthe pressure line 18 in application of the pressure to either one of thecontrol lines 52 or 54, all substantially as described and claimed inthe U. S. patents to Blanchard et al. 2,307,101 and 2,307,102 grantedJanuary 5, 1943.

To properly condition the potential of pressure in the line I8 and keepit impressed to a suflicient extent to meet the needs called for by thegovernor valve, there is a pressure control unit I and the accumulatorcontrol valve assembly I4 connected into the fluid circuits between thepump 80, the governor 56 and the accumulator 62. The accumulator feedline 12 communicates with a chamber I02 of the assembly 14 which chamberis controlled by a trip and filler valve I04 selectively operable by acam carrying lever I06 in response to movement of the control ring 98 aswill be presently explained. A feathering and braking control valve I08is embodied in the assembly I4 and normally separates a chamber IIOsubject to pump pressure, from a chamber I I2 normally exposed toaccumulator pressure. A branch pipe I I4 extends from the pump line I8to the chamber IIO which also communicates with the bore I I6 for thetrip valve I04, while a branch II8 from the chamber II2 extends to achamber I20 on the under side of a land or piston I22 carried by thevalve I08. The branch pipe II4 also connects with a chamber I24 housinga pressure control valve plunger I26 that has a land I28 controlling aport I30 leading to the valve bore I32 of a minimum pressure controlvalve I34, both of which are situated in the pressure control unit I00.The minimum pressure valve provides a land I36 that controls an exhaustport I 38 emptying into the reservoir I6 such that escape of fluid underpressure from the valve I26 must build up to a predetermined valuethrough the port I30 before it can spill into the reservoir. Furthercontrol of the spill is effected by a fluid connection I40 opening tothe back side of the land I28 and connected to the increase pitchpressure line 54.

With the pressure developing means and pressure controlling meansorganized as described, the operation will be in substance as describedand claimed in a co-pending U. S. application Ser. No. 616,808 filed inthe name of D. A. Richardson et al. for Accumulator control unit, andwhich may be briefed as follows. Actuation of the pump which draws influid from the reservoir I6 through the pump intake I42 creates pressurein the pressure line I8 which penetrates to the pressure control valve,the accumulator valve and to the governor valve. At the pressure controlvalve the land I28 is urged inward to uncover the port I30 in oppositionto the pressure from the increased pitch port through I40, and whichcontrols in conjunction with the minimum pressure valve, the potentialof pressure existent in the passages H4 and I8. That pressure exertsitself in chamber H0 to open the valve I04 for charging the accumulator,and surrounds the valve I08 as well as presses upon the piston I22. Thedistribution of pressures upon the valve I08 is such that it normallyremains seated against relieving pressure in the accumulator. However,upon unseating the valve I04 by the lever I06 the high pressure of theaccumulator is admitted to the under side of the valve I08 and thepiston I22 to afford direct communication between the chamber I02 and H0through the chamber II2, thereby exposing the potential of theaccumulator to the branch H4 and pressure passage I8 to the governorvalve. The accumulator is open to the pressure line only upon definiteand predetermined positioning of the control ring 98, and during whichtime one of the control lines 52 or 54 is wide open at the governor toreceive the additional flow from the accumulator. As soon as that flowstops, as a result of the completed movement of the piston 40 that iscalled for by the governor, then the pressure differentials applied tothe valve I26 are reduced and it reseats ready for a subsequentoperation of the control mechanism.

Selective control of the governor valve 56 and the accumulator controlvalve I4 is efiected by predetermined movement of the control ring 98,which is accomplished by high-lead screws I44 threading therethrough andhaving a journal bearing in a flange I46 of an adapter sleeve I48 pro'jecting into the regulator 58from a'-"fixeil=-sup-' port'on thenosing'fll. Pin-ions I 58 secured to the end of each of the screw'shaits I44 'meshwithan internal "toothed ring gear I52- that issupported on the adapter sleevei ifloutside of theregulat'or58, theringgear havinga control' lever I54 actuatable by suitable-linkageiromthe cockpit of the craft. The adapter sleeve I 48 isprovided with "alug Itdengageable within=a notch I 58"'on the support Illforrestrainin'g rotation of' the adapter assembly when the regulatorrotates. The ring gear 'l52,iian'ge l46,*screw shaftsI M, and controlring 98 are tl1ereforehe-1d stationary within the regulator 58 while ithe latterrotates around them, and particularly the flange M6 which isprovided with-a series of 'teethtfifl fiengageable with a pinion I62 of'th'e pump 80 f'or driving'it upon rotation ofthepropeller.

:The linkage connecting the lever I54 "to :the pilots compartment maytake various forms, but in the present instance incorporates a-frod 155provided with a yoke or otherz'pivot'alvconnection I5'I with the leverI54 and a second yoke or. pivotal connection [6-D with-amid point of alever or crank arm I63 secured to asha'ft extendingiromran actuator'unitI 64. The actuator'zunit may::be rigidly afiixed to any convenient :partof lithe supporting structure near the ring geargandthe lever I62 isconnected by a: Bowden wire zor'rflexible cable I66 housed withinasheathlfiB, toa-xa control lever or m'anual leverfmeans .or thee lihe Ipivotally supported at I12 in the-cockpit near the' pilot, substantiallyas indicateddniFig. 2:0f. the drawings.

:The actuator unit ltfluzhouses a motor and mechanism for oscillatingthe lever IBZ-zineeither direction for controlling the "movement of :thelever I 54 and consequently the; movementuofz the f ulcrum roller 86 andthe lever I 86. :Thes lever I62 has one end in driven relation uponlashaft or'hub I'M that carries a large gear I16, meshing witha pinion H8looselyretained and; rotatable uponashafttfifi. Thevpini'on I18 haswaclutch face l82 engageable with:.-aucooperatir1g clutch face 9 I84'sliclable but "non-rotatable relative :to the shaft I8!) that 1 isdriven by za'aworm whee'l I88. A spring i'sll encompassingvthe"shaft?I80and extending between-the wormwheel Hill-and anarmature disc I86 carriedbythe' clutch member I84 operates norma'lly: toxmaintain the clutchmembers I82 and $84 :inrdriving engagement. sa solenoid coil I92iszdisposedstomei in attractive irelation to the armature disc IBfisothat its energization will operate to:o.pen the clutchnmembers 182 andI84. Aworm I94drives theeworm'wheel end-"of a motor shaft 1 202.0%. a.reversib'lerrnotor 204. "The :motor 284 isipowerediby a-v-c'urrentsource such as a batteryizilii throughaagpower :lead or cable 288electrically controlled by a-two;position switch 2Ill. Branch connection:2I2 ofthe cable208 joins acabIeZMleading toftheasolenoid 'l 92 while acable 2 I 6 joined theretoleads toa push button switch 2I8 mounted onthe :manuahililfl andaffords selective control for energization-rof thesolenoid.

A measured shift .or the blade pitch; such 'asia bhange' in the speedlevel at which the-regulator mechanism is to control for constantspeed,:.:is nowefiected by the pilot fii-pping" the-:sWitchElZII] to'the proper position, which may be up with respect to the drawing forincrease pitch setting and down' for decrease pitch setting, -In' eitherbe energized to "drive the shaft 2M, worm 28d, worm-wheelI98,worml94,worm wheel I 88, shaft I and-= clutch member 184. If the Iclutch faces I82 and I84 are in engagement the pinion H8 will be drivenas will also the gear I76 which-turns the shaft I I M --and swings the=leverl-t2 through anarc and causes a reciprocation of the link* I55witha'consequent' arcuate movement of thelever F54 and 'ring gear 4 I52on the adapter assembly. Movement of the ringgear -I-52 actuates thepinions I50 which by the-attached screw 'shafts moves the control ring98 fore or aft along the axis of the regulator-and in so moving pushesthe carriage-Stand its fulcrum roller 85 along the length of-tlie'gui'deways-96 and governor'lever 84. Changing the position ofthe fulcrumrol-ler 86- relative to the lever 84 4 alters the 'relation' o'f forces,centrifugal and spring, acting upon the valve plunger 82 and-inconsequence sets up-a new-set" of conditions at-which the valve-wtll bein the equilibrium'condition. When the desired setting 'has beenattained, the pilot opens the switch 2 I8-and-the motor 284abruptly-stops because of the lack of driving energy and theoperation ofa built-in brake that-takes efiectimrnediately that current'tothemotoris-cut off.

A quick or instantaneous shift to-either' ieatm ered pitch or "negativepitch for braking may-be effected by the pilot upon movement of themanual levermeans or'thelike no. "The-gear train between the motor shaft202 and the-oscillating shaft I 74' is of great ratio,'such*as of theorder of 20,000 to 1,-which results m an irreversible gear connection bywhich any movemeritOf the lever I62 can "effect movement-of the geartrain. The ratio of gears alsoprovides a slow movement of the lever I62for any rna-terial'rotation of the motorshaftgancl consequentlycoastingof a'fewturns of the motor shaftfollow-ing current interruption does notmove the lever162=or anything connected -toit beyondthe point ofselected setting. Thus when the pilot "desires to move the lever II'Il,he also closes the switch 218 which energizes the solenoid I=92and-effects -attraction of the'armat'ure disc- I86 for opening theclutch. 'With-the 'clutchopened then'the lever 'I-IU being-moved willsuue the cable I66 within the 'sheath IBBan'd cause oscillation of'thelever l62 and reciprocation of -thelink Ifilito actuate the propellercontrol lever I54. Oscillation of the lever I62 will effect rotation ofthe-gear "I16 and the "pinion I18 freely on the 'shaft- I88, since thedisengaged clutch at I82 and IM does'not causerotation of the rest ofthe gear train'to the motor. The result is, that movement of the leverI10 causesmovement of the carriage 94 alongthe ways-Silas has-beendescribed. If" the lever I10 is i -move'd toone:extremethenthe carriage:is moved 'to' a position for feathering" the blades-of the propellerand if '.the 1ever*is-rnoved to the opposite extreme their the carriage:is moved to -a position' for brakingv'which is in the reverse 101'negative'pitch position. When the carriage f9 4'- moved to thefeathering position .the control ring 98 also? actuates the cam carrying.lever= 106 that moves the-tripping valve I84 so that the full force ofthe "accumulator may.;be :applied .to :the governor valves oftheregulator. In order-to unfe'a'ther the propeller ;blades,i the lever I18715 moved out :of the-feathered position,: -which, :by thev linkagedescribed partially-returns the: carriage 94 toward .theegoverning;position: and also retrips the trip valve I04 which exposes the chargeof the accumulator to thegovernor valves.=:oi, the regulatomand resultsin rotating-the:blades put of their feathered position. When thecarriage is moved to the braking position, at the out end of the lever84, there is no movement of the lever I06, but the governor valve is sodisturbed that it will open wide the ports of the decrease pitch linewhich effects movement of the blades through their zero pitch setting toa negative value and thereby reverses the thrust of the propeller thoughthe direction of rotation remains the same. In any instance, movement ofthe manual lever ill) from either extreme position to an intermediateposition quickly returns the blade setting to the range where thegovernor is effective to control the propeller to constant speed.Instead of instantaneously attaining the governed pitch setting bymovement of the lever HD to an intermediate position, the same may beaccomplished over a longer elapse of time by use of the switch 2|0.Moving it to the proper position and leaving it there long enough willcause the blades to gradually move from any governed pitch setting toeither the feathered position, or to the braking position, or fromeither of the extreme positions, i. e. braking or feathering, back to aselected governed pitch setting. When the desired setting is attained,opening of the switch 2H! Will stop the shift, and the governormechanism will pick up from there and control the propeller to theconstant speed selected.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. In a constant speed aircraft propeller having pitch shiftable blades,a source of power and mechanism for shifting the blades throughout arange of pitch setting, with selective control means Working upon theshifting mechanism and including a lever for control of the pitchsetting of the propeller, means for actuating the lever, comprising incombination, an electric motor with gearing for actuating the lever inslow motion in ither direction, switch means and a current source forcontrolling the operation of said motor, a manual control means foractuating the lever and embodying a clutch and circuit connections forinterrupting the motor gearing to said lever whereby manual fastmovement of said lever may be accomplished.

2. In a constant speed aircraft propeller having pitch shiftable blades,a source of power and mechanism for shifting the blades for feathering,governed pitch, or braking, with selective control means working uponthe shifting mechanism and including a lever for control of the pitchsetting of the propeller, means for actuating the lever, comprising incombination, a reversible electric motor with speed reducing gearingending in a crank arm for actuating the lever in either direction, saidgearing including a normally closed clutch but separable forinterrupting the gearing adjacent said crank arm, a manual control meansfor actuating the lever directly in lieu of motor operation, and meansincluding a current source, clutch shifter and switch means forcontrolling the motor operation and gear connection to eifect selectedrapid and slow movement of the said lever, whereby feathering pitch andbraking pitch for the propeller may be superposed upon the constantspeed control of said propeller.

3. In a constant speed aircraft propeller having pitch shiftable blades,a source of power and mechanism for shifting the blades throughout arange of pitch setting, with selective control means working upon theshifting mechanism and including a lever for control of the pitchsetting of the propeller, means for actuating the lever, comprising incombination, a reversible motor means, a crank arm operatively connectedto the said lever, speed reduction gearing connecting the motor and saidcrank arm, a clutch mechanism in the gearing for connecting anddisconnecting the motor with the crank arm, and means operable upon theclutch for controlling the said gear connection.

4. The combination set forth in claim 3 wherein'the means operable uponthe clutch comprise a solenoid and armature adapted to disengage theclutch mechanism.

5. In a constant speed aircraft propeller having pitch shiftable blades,a source of power and mechanism for shifting the blades throughout arange of pitch setting, with selective control means working upon theshifting mechanism and including a lever for control of the pitchsetting of the propeller, means for actuating the lever, comprising incombination, an actuator unit outside of the propeller mechanism havinga crank arm for actuating the said lever directly, said actuator unitcomprising a motor and an interruptable gear train for slow movement ofsaid lever, and means remote from the actuator unit for controlling theoperation of the motor and gear train.

6. In an aircraft propeller having pitch shiftable blades and controlmechanism for shifting the blades in feathering pitch, governed pitchand negative pitch by a power source applied to the control mechanismthrough the action of a selectively operable control lever fordetermining the character and amount of blade pitch to be elfected bythe control mechanism, remote controlled means for actuating the controllever comprising in combination, a reversible electric motor andreduction gear train having a crank arm operatively connected to saidcontrol lever, a normally engaged clutch in the gear train tending tomaintain driving relation from the motor to the crank arm, a solenoidoperable when energized to disengage the clutch, a source of current andswitch means for control of the motor operation, manually actuated meansfor overriding the motor driven means in actuating the control leverincluding a directly connected member for fast movement of the crank armwhen the clutch is disengaged, and a switch for controlling theenergization of said solenoid to disengage the clutch when the motordriven means is overridden.

7. In an aircraft propeller having pitch shiftable blades, motor meansfor shifting the blades, and pitch control means for directing theapplication to the motor means of power developed by rotation of thepropeller for effecting feathered pitch, governed pitch, and negativepitch, with said pitch control means providing a control lever fixedrelative to the rotating propeller and adapted to select the pitch underwhich the propeller is to operate, remotely controlled means foradjusting the control lever comprising in combination, a slow speedcontrol including a speed reduction gearing terminating at the drivingend in a crank arm operatively connected to actuate the control lever, areleasable clutch normally connecting the gear train with the crank armfor actuation thereof, a high speed reversible motor for driving thegear train to actuate the crank arm at slow speed, a source of power andcontrol means train when the crank arm is operateti by the manuallyactuated means.

HOWARD M. GEYZER. HOWARD CARSON.

REFERENCES CITED The following references are of record-in the file ofthis patent:

Number UNITED STATES PATENTS Name Date King July 10, 1900 Pearson May 9,1937 Martin, Jan. 17, 1939 MacNell et a1 Oct. 20, 1942 Martin May 18,1943 Richmond July 4, 1944

